[Online Sources about Atmospheric Fine Particles During the 70th Anniversary of Victory Parade in Shijiazhuang]

Robust measures were taken to ensure a good air quality for the parade on the 70th Victory Memorial Day for the Chinese People's War of Resistance against Japanese Aggression (VM Day). During the period, the source of fine particulate matter in air was analyzed with the single particle aerosol mass spectrometer (SPAMS) located at Shijiazhuang air automatic monitoring station of 20 meter. The results indicated that, on VM Day the primary sources of air pollution were vehicle exhaust emission (20.9%) and coal-generated emissions (20.6%), which were also at lower degrees than those on pre-and post-VM Day. It turned out that these air quality-improving measures, especially the vehicle restriction and coal consumption reduction, had a good effect. Particles from the vehicle exhaust and coal combustion source were mainly based on short-chain elements, carbon, manganese and organic carbon. The particles from the industry source were mainly organic carbon and metal. Particles from the dust source were mainly composed of silicate and calcium. When air quality-improving measures were stopped, the concentration of particulate matter rapidly rose again, and the contribution of dust and vehicle exhaust emission was remarkable. It was believed that the interaction of low-pressure static stability of adverse weather conditions and southeast direction of low altitude transmission was a major cause in the deterioration of air quality.